Bending machines



A11@ 6, 1957 J. H. HAwEs 2,801,559

BENDING MACHINES Filed July 25, A195s /5 l y 34/ i////VV///`, /////z -L- /6 v VIII... .Il

. BENDING MACHINES John Henry Hawes, London, England, assignor to Hilmor Limited, London, England, a British company Application Jury 2s, 1955, seriaiNo. 524,257 Claims priority, application Great Britain July 27,l 1954- 1 Claim. (Cl. 81-15) This invention relates to a bending machine for pipes, tubes, sections, solid bars and the like which are herelnafter referred to` as tubes In conventional tube-bending machines, the bending head has been made of two substantially triangular shaped plates `located above one another `and `spaced apart by,

and welded to, a member located at their apices, the tube being forced between two lixed stops located between` the triangular shaped plates, by a forming tool moving along` a line or path which divides the triangular shaped plates into two equal triangles, the forming tool being moved along the said path by a ram which` is connected,

to thegspacing member. The two plates are provided with a series of holes so that the distance of the stops from the said path can be varied.

The chief disadvantage of this type of bending machine is `that it is impossible to form more than one bend in a tube in any given plane relative thereto unless the distance between the two bends is `such that one of the bends is spaced from the centre `of the second bend a distance greater than the distance between the edge of ram and` a forming tool engaged' bythe ram alongj aj, straightr path, `amounting member mounted `in said` guiding means at the end of said p-ath remote jfrom the` ram which mounting member is adjustable by movement` transverse of` said path, locking means for locking the one end of the mounting member, a second stop mounted on the mounting member with its axis adjustable along the length of the mounting member, fand `second locking means toloclcthe second `stop against'linear movement relative to :the mounting member.

In use `the mounting member is adjusted relativetothe` guiding `means and the second stop is adjusted to a posi tion on the mounting member, sothat the second stop and the. first stop lie on opposite sides of said Apath and are equally `spaced from" said path, the spacing of .the stopsbeing chosenin accordance" with` the bend,`tobe produced., w H t One embodiment of the invention will now be described by way of example with reference to the accompanying drawings, of which:

Figure 1 is an elevation of a bending machine,

Figure 2 is a plan of Figure 1,

Figure 3 is a section on the line 3--3 of Figure 2,

Figure 4 is a section on the line 4-4 of Figure 2, and

Figure 5 is a section on the line 5 5 of Figure 4.

The three-point bending machine shown in the drawings has a ram unit which comprises an elongated threaded rod which engages a block 11 having a tapped bore. One end of the rod 10 is adapted to be operated by a a" three-point i arent Q mounting member relative to the guiding means, a'iirst stop mounted on the mounting member with its -axis ixed relative to the mounting member and adjacent haud tool and is shown as having a square end 12 `for `a ratchet lever, whilst the other end, on the other side'gofw the tapped block 11, is provided with a cylindrical .ex-

tension `13 (Figure 4) which is rotatably received in and axially located in a recess located ina grooved rectangular block 14. The block 14 is guided by two elongated rectangular plates `15,16 secured to the tapped block 11 i and received within the groovesof the block 14 (seen Figures l and 5), so that, as the threaded rod 10 located in the tapped block 11, rotates, it moves bodily along its longitudinal axis, relative to the threaded block 11` and plates 15 and 16, pushing the grooved rectangular block L 14 before it. u

rThe end of the grooved block 14 remote from the cylindrical recess is provided with a cylindrical projection 17 (Figure 4) ,which engages a recess in a forming tool 18. The grooved block 14 is provided with a hooked` member 19 rotatably mounted on a bolt 21. When it is desired to retract the forming tool 18, the hooked member 191is swung over to engage in an `eyelet 22 mounted on the side of the forming tool 18 so that when the hook engages `the eyelet and thethreaded rod is rotated in the reverse direction, the forming tool moves` with the ram.

The end ofthe lower plate 16 remote from the-tapped block 11.is provided with a groove transverse to the longitudinal axis of the said plate, whilst the upper pl-ate 15 is provided Vwith a hole 23 located above the centre of the` groove in the lower plate. The movable mounting member or bending head comprises two elongated rectangular plates 24,` 25 spaced apart in parallel planes 1and welded together at one end. A rotatably' mounted stop 26 is located adjacent `one end of, and between, the said plates 24 and 25, and its axis relative to the two plates 24 and 25 is lxed since it is mounted to rotate on a pin A further elongated rectangular plate-23 is welded to j but spaced apart from the upper elongated plate 24 of` the bending head suchthatit provides a slot. 29 which receivesthe upper plate 15 of the guide means for the This further elongatedplate 28` is vprovided with .a series of holes 31 `which series extends longitudiy` nally, of `the plateA and` `immediately `below `them `arey a series `of aligned` holes 32 in the upper plate 24 whichV ram unit.

are tapped.

`In order to loclcthe bending head "tothe, `ram `uriit one"u ofthe holes 31 and the aligned hole32 are aligned vvith` the hole 23 inthe `upper guide plate715 of the ram `unit anda threaded pilot pin 33 is passed thro-ugh the holes 31` and 23and screwed into the hole 32. Thisdetermines the distanceof the longitudinal axis of the ram unit from the axis `of rotation of the fixed stop which `can be varied i byselectingthe `appropriate pair of `liolesiiil and `32 andl `j until they'are aligned with the 1 sliding the bending head hole23. i M.

The two plates 24 and 25 of the bending head are provided, on the side of the ram unit remote from the xed stop 26, with a second series of aligned holes 34 and 35 located along the longitudinal axis of the two plates, the lower holes 35 being tapped to receive a threaded pivot pin 36 whilst the holes 34 in the upper plate 24 are `of such a diameter as to provide a clearance for the pivot pin 36. The pivot pin 36 provides means for rotatably mounting a second stop 37 at varying distances from the longitudinal axis of the ram unit while locking the second stop 37 against linear movement relative to the bending head.

Patented Aug. 6, 1957 In use, the second stop 37 is located between the plates holes 34, 35 in the second series corresponding to the pair of holes 31, 32 in the rst series into which the` pilot pinV 33 has been, inserted;VV Thentlie pivot pin 36l is passed through,the'appropriate hole 34; and the,

alignedbore 38`r of the second-stop and is' screwedfinto the aligned hole 35:

"There are the samehumber of'pairs ofholes 34, 35 in n hole 23 the centre of the pair -of holes at the right hand end of the second series and the axis ofrotationof'the xed stop are equally spaced fromV the axis of the threaded rod on opposite sides thereof. Further the spacing between thecentres ofl adjacent/,pairs of alignedholes in the second series is twice'the spacing between, the centresy of'adjacent corresponding` pairs of holes in the iirstl series.

Both the stops are substantially triangular shaped in plan and are provided along the length of the sides opposite the apices with semi-circular grooves which normally contact the surface of a tube during bending and the length of the grooved sides of the stops is sufficient not to dent a tube which is being bent as frequently occurs with the circular sectioned stops hitherto employed. The apices of the triangularV shaped'stops are partly rounded and are also provided with a semi-circular annular groove the centre of which is located in the plane` of the centre of the thickness of the triangular block. The stops are dimensioned so that, when the straight grooved edges of the stops are'parallel to the edges of the plates 24, 25,'the vertical tangent in Figure 1 ofthe groove is to the left of the left edge of the plates 24 and 25. The fixed stop is provided'with a series of gradations 40 which indicate against a marker on the plate 24 the number of degrees to which the tube has been bent.

In operation, the transverse position of the bending headrelative lto the ram unit is fixed for bending a tube of a certain diameter. The distance of the axisof the second stop from the longitudinal axis ofthe ram unit is set up so that it is equal to the distance of the axis of the xed stop from the same longitudinal axis. Thus,

when a tube is locatedl in the two semi-circular grooves in thestops and the forming tool is moved towardstthe tube by the ram unit, the forming tool contactsthe tube at a pointmidway between the axes of the two stops and the tube is at a tangent to the curvature of the` forming tool. As the ram unit is moved forward,l the tube is bent to the shape ofthe forming tool whilst both the stops rotate inwardly towards the longitudinal axis of the ram unit, the degree, of bending being indicated by the gradations on the fixed stop.

It has been found that, in the machine described',v a bend of any radius can be producedA in any plane in a tube which has an existing bend since the existing bend can be located at the end of the bending head at which the fixed stop is located, and is free for rotation through 360 whatever the diameter of the tube, so that a bend may be produced in the tube, even close to the existing bend in any plane relative thereto.

plates 15 and 16 ensures that when an offset bend isbeing made no out of balance transverse load is transmitted to the threaded rod 10 of the ram unit.

The ram unit may be provided with bored feet 42 by which it may be attached to a bench or stand and with a plate-like projection 41` which may be clamped in the jaws of a vice.

In the above example, the ram is advanced by means of a1 threaded spindle, but it will'be appreciated that the invention can also be used in three-point bending machines which have a ram advanced by any of the known methods.

I claim:

AV three point bending machine comprising a forming tool, a ram which is adapted to engage the forming tool, guiding means for guiding the ram and the forming tool engaged by the ram along a straight path, which guiding means has a surface vwith a hole in it'adjacent the end of the guidingmeans remote from the ram, a mounting member comprising two elongated rectangular plates spacedapart from one another in parallel planes andintegrally connected together at at least one end, one of said plates having aV first series of holes in it spaced from one another, which series of holes extends longitudinally of said one of said plates and said one of` said plates having a surface in sliding engagement with said surface of said guiding means, a first pin located and fitting-in one hole of said rst series and in said hole in said-V surface of said guiding means to lock said guiding means and said mounting meansagainst sliding movement relative to one another, a rstrotatably mounted stop mounted between saidl plates to rotate about a fixed axis at the end of said plates remote from said one end, said plates the one having a secondy series of holes in it and the other a third'series of holes in it, which second and third series of holes extend longitudinally of the plates, there being an equal number of holes in the second and third series and the number being equal to the number of holes intherst series, the holes in the second series being aligned with those in the thirdv series and the spacing between adjacent holes in the second series and in the third series being twice the spacing between corresponding adjacent'holes in the iirst series, a second pin locatedA and tting in the hole of the second series and the holev of the third series which corresponds with the hole in the rst series in which said rst pin is located, and a second stop having a bore in it, which second stopA is rotatably and removably mounted on said second pin and between said plates, said second pin passing through said bore in said second stop.

References Cited in the file of this patent UNITED STATES PATENTS 

